it works fine initially, but for long term it's usually more productive to have custom software.
If you multiplied the custom software development effort and cost to the multitude of places and use cases people in an organization are using spreadsheets I think you’d quickly find that it’s infeasible. And that’s not even taking into account how much value the adhoc-ability of spreadsheets adds to the equation. Most spreadsheets can be completely refactored or thrown away in a rather trivial manner. The sprint nature of software development screens out most things that could be spreadsheets. I’ll build it in an hour instead of waiting 2 weeks to get on the next sprint.
The software development process is too rigid for rapidly changing business needs. Having to spec out requirements and such is often an unknown and something you’re doing live in the moment when creating the spreadsheet itself.